This migrates the above files from tempest. This includes tempest commits:
* quota_classes_client.py: Idd8afb1bcfc1b0165b1e967a991d4705ff182249
* test_quota_classes_client.py: I3ad6761651cec5e66012d08e6b63322f53286a5c
* quota_classes.py: I2378e019353f551a3ac49666edd5ecb561b5b6ed
to see the commit history for these files refer to the above Change-Ids
in the tempest repository.
Partially implements blueprint migrate-service-clients-to-tempest-lib
Change-Id: I48ce2ddf21218eb02f6ae47cb0356c340ced06ae